1. Field of the Invention
The present invention relates to a vehicle steering wheel. Particularly, the present invention relates to a steering wheel constructed with an air bag unit. More particularly, the present invention relates to a steering wheel capable of absorbing the energy of a forward impact, even if applied to the rear side of the ring portion, and to a steering wheel able to absorb impact energy.
2. Description of the Related Art
A prior art air bag equipped steering wheel constructed for absorbing impact energy, even if applied to the rear side of the ring portion, is disclosed in Japanese Laid-Open Patent No. 278861/1992.
The steering wheel, as disclosed in the above disclosure is constructed with notches in the core bar of the spoke portion at the rear side. Moreover, the core bar of the rear spoke portion plastically deforms when impact energy is applied.
In the disclosed steering wheel, however, only one of the spoke portions of the rear side deforms. As a result, the disclosed steering wheel may be unable to sufficiently absorb the applied impact energy. The reason for this is when the notched core bar of the spoke portion deforms, it makes contact with the column cover which is arranged below the steering wheel. This contact regulates (or interrupts) the deformation. If the spoke core bar fails to plastically deform, some impact energy is not converted into energy used for plastic deformation but remains undissipated. In short, all the applied impact energy cannot be sufficiently absorbed.